All over the United States, there are dams, dikes and navigation dams, utilized to control water flow, that are relatively low-head structures which can be used for power generation without excessive civil engineering construction. These structures in present day energy shortages can be made to produce energy at competitive rates to users. A major problem of the existing dam structures is that the spillways that are provided must be capable of handling flood water conditions. However, known power generation units require new powerhouse and foundation construction or major dam reconstruction to accommodate turbine installation. Under this approach, the existing sites will not be feasible because they usually exist where an increase in head is not possible and the reconstruction cost of the dam site cannot be economically justified.